JP2014187866A - Squirrel cage rotor, individual members thereof and method for manufacturing squirrel cage rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further deploy a joint coupling part of a squirrel cage rotor.SOLUTION: The squirrel cage rotor, in particular for use in an asynchronous machine, comprises a shaft, a rotor metal plate stack with cage bars arranged inside, and a plurality of short-circuiting rings. At least a part of the short-circuiting rings is formed from a disk laminate, the disk laminate is formed from a plurality of disks including a plurality of recesses in layers, and through the disks, an end portion of the cage bar is passed from the rotor metal plate stack. The disk of the short-circuiting ring includes at least one chamfered portion or step portion radially directed inward from a jacket surface as an end face side to the outer circumference. Neighboring disks form one groove in the disk laminate from the chamfered portions or the step portions and within the groove, a joint coupling part is present at least partially.

Description

  The invention relates to a squirrel-cage rotor and its individual components according to the prerequisite technology of claims 1, 12 and 13, respectively, and to a method for the manufacture of a squirrel-cage rotor according to the preamble of claim 14.

  In known squirrel-cage rotors, a rotor metal plate stack with closed grooves comprises a plurality of squirrel bars made of well-conductive material embedded in the grooves. The end portion of the rotor protrudes beyond the end face side of the rotor metal plate laminate, and is hard soldered to a compact short circuit ring. The end of the squirrel-cage bar projects into a ring groove screwed in the short-circuiting ring, which forms a foundation for the hard solder and is filled with the hard solder. The result is a relatively large requirement for hard solder. On the end face side, individual compact pressure rings are pressed against the rotor metal plate stack in order to prevent the rotor metal plate stack from spreading and disturbing vibrations. Furthermore, in order to prevent axial displacement of the cage bars into the grooves of the rotor metal plate stack, these cage bars are mechanically consolidated to the rotor metal plate stack.

  Patent Document 1 discloses a squirrel-cage rotor having a squirrel-cage winding. The squirrel-cage winding includes a conductive squirrel-cage bar that is disposed in a closed groove of the rotor metal plate laminate and projects beyond its end face. The protruding end is conductively coupled to a plurality of short-circuit rings that are well conductive. These short-circuit rings are formed of a metal plate laminate having a groove and made of a material that conducts well in accordance with the rotor metal plate, and the pressure member on the end face side transfers heat over the entire surface. Close to the rotor metal plate stack, it is consolidated in its closed groove with a squirrel bar. One feature is that the conductive individual metal plate for the short ring has a greater thickness than the rotor metal plate, but otherwise has the same shape and size. There is. When manufacturing a cage rotor, a plurality of short-circuit rings and a rotor metal plate are commonly packetized and provided with a cage bar that is pushed in on the end face side, and then the axial direction of the common laminate The end of the squirrel bar is hard soldered to the short circuit ring under the pressure of.

German Patent Application Publication No. 3421537

  It is an object of the present invention to further develop the joint connection portion of a cage rotor.

  The invention is depicted by the features of claims 1, 12 and 13 with respect to the cage rotor and its individual members and with the features of claim 14 with respect to a method for the production of a cage rotor. The other dependent claims correspond to preferred forms and developments of the invention.

  The present invention includes a shaft, a rotor metal plate laminate including a cage bar disposed therein, and a plurality of short-circuit rings, and at least a part of the short-circuit ring is formed of a disk packet, The disk packet is composed of a plurality of disks having a plurality of recesses in a stacked manner, and the end of the cage bar passes from the rotor metal plate laminate through the disk, and the disk of the short-circuit ring At least one chamfered portion or step portion oriented radially inward from the jacket surface as a side to the outer periphery, and the adjacent disk is the disk packet by each of the chamfered portion or stepped portion. 1 includes a squirrel-cage rotor in which at least a part of the joint is present in the groove. This squirrel-cage rotor is provided especially for use in asynchronous machines.

  In this case, the present invention is based on the consideration that the rotor metal plate stack results in a compact squirrel-cage rotor after the joining process together with the shaft and the short circuit ring. In the rotor metal plate laminate and the short-circuit ring, a plurality of squirrel bars are penetrated, and these squirrel bars are conductively coupled to the material of the short-circuit ring. For this reason, the squirrel bar has an excessive length with respect to the rotor metal plate stack, so that this length projects into the short-circuit ring in the recess. The short ring is positioned on the shaft on both sides of the rotor metal plate stack. Each shunt ring itself consists of a disk stack composed of a plurality of individual disks having the same diameter. These disks themselves have as many recesses on the disk surface as a squirrel bar required for assembling a squirrel-cage rotor. Initially, these individual members, which are arranged separately from each other, need to be combined into a compact squirrel-cage rotor. For the formation of the joint connection, the end face side of the disk is provided with at least one chamfered part or step part on the basis of the jacket surface of each short-circuited ring. If the geometrical shape of the disk is regarded as a cylinder, the jacket surface is the outermost range of the surface in the surrounding surface or peripheral surface on the end surface side, that is, in the radial viewpoint direction. The bottom surface or top surface of the cylinder is a surface perpendicular to the rotation axis. As a result, a plurality of adjacent disks arranged so as to form a disk stack includes a small gap as a groove by a chamfered portion or a stepped portion. In addition, a joining joint part can be formed along this clearance gap. A groove between each disk extends around the periphery of each disk stack. The chamfer and step are, in the preferred embodiment, formed in the disc so that they extend radially to the recess for the squirrel-cage bar. In this way, grooves are formed that can reach the level of the cage bar in the radial direction. In order to join the individual disks in the disk stack to the squirrel bar, a joint joint is formed along the groove that connects the individual members together mechanically and electrically. There is only one joining surface between the adjacent disk surfaces of adjacent disks.

  Instead, the bar extracted from the metal plate laminate cannot be exposed in the range of the groove formed by the chamfered portion or the stepped portion. The plurality of recesses in the disc are positioned somewhat in the groove of the disc when viewed radially, i.e. inward in the radial direction, but so that the bar is located within the melting region during welding. Thus, the bar area in the vicinity of the groove is circulated by the melt produced by the laser beam or electron beam during bonding and is conductively coupled to the disk. At this time, it is essential that there is only one joining surface between the disk surfaces of the adjacent disks contacting each other.

  In other words: therefore, freely accessible openings extend radially between adjacent disks until the level of a squirrel bar is reached so that the individual members can be joined together electrically and mechanically Yes. In this way, sufficient electrical contact is made for the feed line for operation of the asynchronous machine. The recess provided in each disk is adapted to the squirrel bar in its shape and size. Therefore, these recesses can be positioned with a slight gap. At this time, the disk of the short ring can be configured as an individual member that is planarly closed with a band material or can be processed as an open disk in the same manner as the snap ring. The plurality of recesses in each disk can be subjected to, for example, electric discharge machining, drilling, or punching. It is also conceivable that each disk is provided with a structure that creates a favorable gap with respect to the joint joint, although it is slight at the contact surface with the adjacent disk. As a result, other regions for the joint joint can be formed deeper in the radial direction beyond the range of the chamfered portion or the stepped portion.

  A special advantage lies in having a sufficient mechanical strength of the whole member due to the joint area in the area of a sufficient groove, although narrowly defined. Similarly, satisfactory electrical coupling with the shorting ring of the squirrel bar occurs. Further, in the joining method that proceeds at a high temperature, local heating occurs only in the joining gap between the two disks without thermally damaging other members and particularly the rotor metal plate laminate. Alloys used in shorting rings often have sufficient heat transfer due to their good electrical conductivity. Thereby, the thermal energy applied at the time of joining is removed rapidly by heat propagation. As a result, the individual disks are joined and strongly joined to each other in the outer peripheral range. Depending on the joining technique, careful attention is paid to the shape and formation of the chamfer or step that ultimately defines the joint gap. The chamfered portion itself may be, for example, a flat surface that forms a V-shaped groove with the adjacent disks in a joined state in each disk. On the other side, it is also conceivable that the chamfered part has a parabolic shape so that a U-shaped groove is produced in the joined state. Depending on the joining technique, a geometrically reasonable joined joint can thus be obtained.

  In a preferred embodiment of the present invention, the end of the bar may be conductively joined to the disk stack of the short ring. Usually, mere joining of the ends of the bars in the short circuit ring results in poor electrical connection. The desired conductive connection is achieved by the material of the individual disks being temporarily and locally melted and the adjacent disks being joined to the material at the end of the bar along the joint gap. On the other side, it is also conceivable that the conductive connection is formed by an additional material, for example a hard solder, provided in the groove-like area. In such a joint connection part, the groove formed by the chamfered part or the step part usually reaches some depth, and as a result, the solder material reaches the surface of the squirrel bar at the time of joining. In this case, the groove formed by the chamfered portion or step portion reaches deep in the radial direction until the entire circumference of the squirrel bar can be circulated by the solder. In some cases, the plurality of recesses for the shorting bar are configured to be somewhat larger than the diameter of the bar itself, so that the solder can penetrate axially through the remaining gap. A particularly good electrical connection is thus formed between the squirrel bar and the short ring.

  Preferably, the joint joint extends over the periphery. This sufficiently forms a mechanical and conductive bond. Bonding joints extending around the periphery, i.e. along the grooves, are also preferred during the progress of several bonding techniques.

  In a preferred embodiment of the present invention, the joint connection may be a weld connection or a solder connection. At this time, laser beam welding or electron beam welding is preferable. Such welded or soldered joints are particularly suitable for joint joints extending over the entire circumference. The weld bead generated at this time is generated inside a groove existing between the disks, and in some cases, the groove can be completely filled up to the end face of the disk. In particular when employing additional solder material, the groove is completely constructed by solder bonding. Both joint types produce good electrical conductivity in relation to mechanical strength.

  In a preferred embodiment of the invention, the disc can have a thickness of 2 to 10 mm, preferably 3 to 6 mm. With this preset disc thickness, it is possible to assemble one complete short ring in advance with about 3 to 5 discs. This correspondingly reduces the number of junctions and, as a result, makes it possible to economically manufacture the short-circuit ring. The thickness of the disc itself is selected such that it is possible to produce individual members, for example from strip material, by stamping or other separation techniques. In particular, at a preferred thickness of 3 to 6 mm, an economical production based on a strip material is guaranteed. On the other side, the disc thickness should be chosen as large as possible so that a complete short ring can be assembled with few discs.

  Preferably, the disk may be composed of a steel alloy or a copper alloy, in particular a Cu—Cr—Zr alloy, a Cu—Ag alloy or an Al alloy. Each alloy selection is based on a precisely metered proportion of the best possible conductivity associated with sufficient strength. The two alloys listed in the preferred selection meet these requirements. Another aspect in the choice of alloy type is also the smallest possible vulnerability to corrosion effects.

  In a preferred embodiment of the present invention, the disk can include two chamfered portions or step portions that are symmetrically positioned on the outer periphery. The chamfered or stepped portions located symmetrically with each other generate grooves formed symmetrically for the joining process in the same manner even when a plurality of disks are joined. The shape of the groove and the size of the groove are ultimately defined by the shape of the chamfered portion or stepped portion of the disk. This achieves an even coupling of the disks in contact with each other in the joining process.

  In a preferred embodiment of the present invention, the squirrel bar can be urged radially toward the center. In operation, a rapid centrifugal rotation of the squirrel-cage rotor generates a radial centrifugal force, and the centrifugal force exerts a large load on the material. A squirrel-cage bar urged radially toward the center prevents this centrifugal force, resulting in a significant reduction in material load, particularly in the area of the short-circuited ring. This material, which is first optimized for good electrical conductivity, can also be used for the formation of a short-circuited ring.

  Preferably, the short ring can be at least partially surrounded by a casing. When using the casing in each short ring, it is necessary to adapt the size of the short ring accordingly. Usually, the casing is filled with a short ring. The outer contour of the casing is usually flush with the outer contour of the metal laminate. In particular, the casing serves to prevent the corrosive action on the alloy of the short circuit ring.

  In a preferred embodiment of the present invention, a pressure ring may be disposed as the casing around a range of the short-circuit ring. This uses additional properties to prevent pure corrosion. The pressure ring that engages around the circumference of the short ring cancels the radial force that occurs when the cage rotor is used. In addition to the mechanically favorable properties of pressure ring, this pressure ring can also be formed so that the pressure ring contributes to the conductivity of the short circuit ring. A suitable material choice is to optimize the pressure ring first with respect to tensile strength and secondly to maintain sufficient electrical conductivity. As a result, the disc and the pressure ring can also be made of completely different alloys. These alloys are optimized for tensile strength and conductivity.

  Furthermore, it is preferable that a closing cover as the casing be disposed on the end face side. The casing cover can also be configured so that the axial bias of the metal plate stack disposed on the shaft and the respective disks are adjusted by the casing cover. This energization plays a role in obtaining a compact structure in the joining process of the individual disks. In addition, the closure cover can again exhibit some degree of corrosion protection. The closure cover can also be a disc at the end, in which the recess only reaches a certain depth into the disc and has no cuts. Thus, the disc side is suitable for accommodating the outer end of the squirrel bar in itself. On the other hand, the other disk side is one flat plane, which closes the short-circuit ring on the end face side. This type of closure cover can also have cooling fins at each end face.

  Another aspect of the present invention includes a disk for a short-circuit ring of a squirrel-cage rotor according to the present invention. In this disk, the end surface side includes at least one chamfered portion or a stepped portion over the outer periphery. The chamfered portion or stepped portion extends in the radial direction to the range of the concave portion where the bar end portion of the squirrel bar can be disposed. Furthermore, the present invention also includes a short-circuited ring of a squirrel-cage rotor composed of a plurality of disks according to the present invention. Here, the disks can be bundled into a single disk stack and stacked in advance in a mechanical or material combination. The coupling is performed, for example, by interlock or laser welding. As a result, a compact short circuit ring is obtained, and this short circuit ring serves as an individual member and can be particularly well integrated into the overall system.

Another aspect of the present invention includes a method for the manufacture of a cage rotor according to the present invention,
The rotor metal plate laminate is disposed on the shaft;
A plurality of short-circuit rings are arranged on the shaft, the short-circuit rings being bundled from a disk chamfered around an outer periphery and having a plurality of recesses into a single disk stack, The end portion can pass from the rotor metal plate laminate through the recess,
-The cage bar is disposed inside the rotor metal plate laminate and in the recess of the disk;
-Joined joints are formed around the periphery in the area of the chamfer or step.

  In a preferred embodiment of the present invention, the disk laminate and the rotor metal plate laminate can be twisted before the joint joint is formed. By twisting the entire stack, the squirrel bar is unscrewed by a predetermined angle parallel to the shaft from its normal position. In this regard, it is usually necessary to form somewhat larger recesses in the metal plate stack and the disk stack in order to allow rotation. Subsequent joint bonding stabilizes the entire structure. It is also conceivable to form the recesses in the metal plate laminate and the disc laminate not only perpendicularly to each disk main surface but also with a certain twist angle. Thereby, the cut is adapted to the twist angle, which allows a slight twist of the laminate or is preset.

  Embodiments of the present invention will be described in detail with reference to the schematic drawings.

It is a schematic side view of a cage rotor. FIG. 2 is a detailed cross-sectional view based on FIG. It is another detail drawing of a short circuit ring. It is another detail drawing of a short circuit ring.

  The members corresponding to each other are denoted by the same reference numerals in all the drawings.

  FIG. 1 schematically shows a side view of the cage rotor 1. In this state, the rotor metal plate laminate 3 is positioned on the shaft 2 and combined with two short-circuit rings 5 that close the rotor metal plate laminate 3 on the end face side. A plurality of cage bars 4 are arranged inside the metal plate laminate 3 and the short-circuit ring 5. The bar end 41 of the squirrel bar 4 protrudes into the recess 51 of the short-circuit ring 5 and ends flush with the last disk 6 of the disk stack 7. In this case, the disk laminate 7 is composed of three disks 6 having chamfered portions 62 and 63 from the jacket surface 64 on the end surface side 61 thereof. A groove 71 formed between the double-sided chamfers 62 and 63 of two adjacent disks 6 plays a role as a joining gap of the short-circuit ring 5. In this case, the first chamfered portion 62 and the adjacent second chamfered portion 63 are formed to be flat and symmetrical, so that a V-shaped groove is formed between the two disks 6. The V-shaped groove reaches the recess 51 as viewed in the radial direction, and the cage bar 4 is accommodated in the recess. Each bottom surface or top surface of the disk 6 is disposed flush with each other. In the joint gap, in FIG. 1, for example, the joint connection by welding or soldering has not been performed yet.

  FIG. 2 shows a detailed sectional view based on FIG. In this case, a groove 71 formed by parabolic chamfers 62 and 63 is formed. In this case as well, the groove 71 reaches the depth of the recess 51 for the cage bar 4. The metal plate laminate 3 ends flush with the end face side 61 and thereby with the jacket face 64 of each disk 6. In particular, such a groove shape is particularly advantageous in laser bonding. This groove shape ultimately supports the guide of the laser beam to a depth in the range of the squirrel bar 4 where a junction bond is to be finally formed. Therefore, the groove depth in the base portion of each chamfered disk 6 shown in FIGS. 1 and 2 is first suitable for laser beam bonding. In addition, the recess 6 that does not penetrate does not accommodate the outermost end 41 of the squirrel bar 4 so that the disc 6 at the end is configured as a closing cover 81. This detailed cross-sectional view also does not show the joint connection yet.

  FIG. 3 shows another detailed view of a plurality A of short-circuit rings, which are connected by a particularly hard soldering or welding as a joining technique. In this case, the bar 4 is extracted from the metal plate laminate 3 so that the bar 4 is still partially exposed to the range of the groove 71 formed by the first chamfered portion 62 and the second chamfered portion 63. Accordingly, the plurality of recesses 51 are still positioned in the range of the chamfered disc. The exposed bar area in the groove is circulated by a hard solder or a melt produced by a laser beam or electron beam during subsequent joining and is conductively coupled to the disk 6.

  FIG. 4 shows another detailed view of A of a plurality of short-circuit rings, which are connected by welding, in particular as a joining technique. In this case, the bar 4 is extracted from the metal plate laminate 3 so that the bar is no longer exposed in the range of the groove 71 formed by the step portion 66. Thus, the recess 51 is positioned somewhat inward of the step of the disk and nevertheless is located in the region of the melting region. The bar area in the vicinity of the groove is still circulated by the melt produced by the laser beam or the electron beam and subsequently conductively coupled to the disk 6 during the joining. The resulting molten bath is not yet shown in FIG.

DESCRIPTION OF SYMBOLS 1 Cage-shaped rotor 2 Shaft 3 Rotor metal plate laminated body 4 Cage-shaped bar 41 Bar end part 5 Short-circuit ring 51 Recessed part 6 Disc 61 End face side 62 1st chamfer part 63 2nd chamfer part 64 Jacket surface 65 Bottom face or upper surface 66 Step 7 Disc laminated body 71 Groove 8 Casing 81 Closing cover A Detailed part

Claims (15)

A rotor metal plate laminate (3) including a shaft (2), a cage bar (4) disposed therein, and a plurality of short-circuit rings (5), wherein at least one of the short-circuit rings (5) The disc stack (7) is composed of a plurality of discs (6) having a plurality of recesses (51) in a stacked manner, and the cage bar ( 4) the end of 4) passes from the rotor metal plate laminate (3), in a squirrel-cage rotor especially for asynchronous machines,
The at least one chamfer (62, 63) in which the disk (6) of the short-circuit ring (5) is oriented radially inward from the jacket surface (64) as the end face side (61) to the outer periphery; Comprising a step (66); and-adjacent discs (6) are arranged in the disk stack (7) by their chamfers (62, 63) or by the step (66). A squirrel-cage rotor (1), characterized in that a groove (71) is formed, and at least partly a bonding joint exists in the groove.   The squirrel-cage rotor (1) according to claim 1, characterized in that the end (41) of the bar is conductively joined to the disk stack (7) of the short ring (5).   3. A squirrel-cage rotor (1) according to claim 2, characterized in that the joint joint extends over the periphery.   A squirrel-cage rotor (1) according to claim 2 or 3, characterized in that the joint connection is a welded connection or a soldered connection.   Cage rotor (1) according to any one of the preceding claims, characterized in that the disc (6) has a thickness of 2 to 10 mm, preferably 3 to 6 mm.   6. The disc (6) according to any one of claims 1 to 5, characterized in that the disc (6) is made of a steel alloy or a copper alloy, in particular a Cu-Cr-Zr alloy, a Cu-Ag alloy or an Al alloy. A cage rotor (1).   The disk (6) comprises two chamfered parts (62, 63) or step parts (66) located symmetrically with each other on the outer periphery. The cage rotor (1) described.   The squirrel-cage rotor (1) according to any one of claims 1 to 7, wherein the squirrel-cage bar (4) is urged radially toward the center.   A squirrel-cage rotor (1) according to any one of the preceding claims, characterized in that the short-circuit ring (5) is at least partially surrounded by a casing (8).   10. A squirrel-cage rotor (1) according to claim 9, characterized in that a pressure ring is arranged as the casing (8) around the circumference of the short-circuit ring (5).   The cage rotor (1) according to claim 9 or 10, characterized in that a closing cover (81) is arranged on the end face side as the casing (8). A disk for a short-circuit ring (5) of a squirrel-cage rotor (1) according to any one of claims 1 to 11,
The end surface side (61) includes at least one chamfered portion (62, 63) or stepped portion (66) over the outer periphery, and the chamfered portion or stepped portion is the bar end portion of the cage bar (4). A disk characterized in that it extends in the radial direction to the extent of a recess (51) in which (41) can be placed.   A short-circuited ring (5) of a squirrel-cage rotor composed of a plurality of disks according to claim 12. In the method for manufacture of the cage rotor (1) according to any one of claims 1 to 11,
The rotor metal plate laminate (3) is arranged on the shaft (2);
A plurality of short-circuit rings (5) are arranged on the shaft (2), the short-circuit rings comprising a plurality of recesses (51), one in a stack from a disk (6) chamfered around the outer periphery; Bound to the disk stack (7), the end of the squirrel-shaped bar (4) can pass from the rotor metal plate stack (3) through the recess,
-The cage bar (4) is arranged in the rotor metal plate laminate (3) and in the recess (51) of the disk (6);
A method is characterized in that a joint joint is formed around the periphery in the area of the chamfer or step.   15. Method according to claim 14, characterized in that the disk stack (7) and the rotor metal plate stack (3) are twisted prior to the formation of the joint joint.

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